There were no reported problems with the helicopter's performance and there were no caution horns during the accident flight, which led the investigation and this analysis to focus on operational issues only. It is quite likely that, during the day, as a temperature inversion existed, katabatic winds formed over the glacier and they were pulsing downhill. Given the gross weight of the helicopter at take-off, the close proximity to the glacier and the strong downflowing winds, the helicopter was not able to climb high enough to clear the surrounding terrain. When the pilot turned away from the lower ridge, the helicopter was settling with power in downflowing wind, and the pilot could not arrest its descent. When the helicopter settled onto the snow, still moving forward, it struck a snow drift, dug in, and rolled over.Analysis There were no reported problems with the helicopter's performance and there were no caution horns during the accident flight, which led the investigation and this analysis to focus on operational issues only. It is quite likely that, during the day, as a temperature inversion existed, katabatic winds formed over the glacier and they were pulsing downhill. Given the gross weight of the helicopter at take-off, the close proximity to the glacier and the strong downflowing winds, the helicopter was not able to climb high enough to clear the surrounding terrain. When the pilot turned away from the lower ridge, the helicopter was settling with power in downflowing wind, and the pilot could not arrest its descent. When the helicopter settled onto the snow, still moving forward, it struck a snow drift, dug in, and rolled over. Given the helicopter's gross weight, its close proximity to the glacier, and the strong downflowing winds, the helicopter was not able to climb high enough to clear the surrounding terrain. When the pilot aborted the departure, the helicopter settled with power onto the snow, dug in, and rolled over.Finding as to Causes and Contributing Factors Given the helicopter's gross weight, its close proximity to the glacier, and the strong downflowing winds, the helicopter was not able to climb high enough to clear the surrounding terrain. When the pilot aborted the departure, the helicopter settled with power onto the snow, dug in, and rolled over. The fact that the helicopter was equipped with stainless steel fuel line fittings and that passenger briefings were enhanced helped to minimize injuries from this occurrence.Other Finding The fact that the helicopter was equipped with stainless steel fuel line fittings and that passenger briefings were enhanced helped to minimize injuries from this occurrence.